Carnitine Palmitoyltransferase Deficiency

What is Carnitine Palmitoyltransferase deficiency?

Carnitine Palmitoyltransferase (CPT) Deficiency is a very rare metabolic disorder that affects the skeletal muscles and their ability to function properly. CPT Deficiency belongs to a group of diseases that involve the defective breakdown (metabolism) of muscle fats (lipids). Prolonged periods of strenuous exercise can trigger an episode of symptoms. These may include muscle aches, stiffness, and weakness. Muscle tissue may break down (rhabdomylosis) and abnormal levels of myoglobulin may be present in the urine (myoglobinuria). The urine may appear dark reddish-brown after prolonged periods of exercise.

The onset of CTP deficiency can range anywhere from infancy to adulthood.

Other names for Carnitine Palmitoyltransferase Deficiency:

  • CPT Deficiency
  • CPTD
  • Myopathy with Deficiency of Carnitine Palmitoyltransferase
  • Myopathy-Metabolic, Carnitine Palmitoyltransderase Deficiency

Condition Subdivisions

  • Carnitine Palmitoyltransferase Deficiency Type 1
  • Carnitine Palmitoyltransferase Deficiency Type 2; benign classical
  • muscular form included; severe infantile form included

CPT Deficiency Type 1 typically affects adults and adolescents. CPT Deficiency Type 2 may also affect adults; however, a serious form of this type of the disease affects infants.

How is CTP deficiency diagnosed?

Several specialized tests are used to confirm a suspected diagnosis:

Blood tests can be used to detect the presence of certain chemicals in the blood that may indicate some metabolic diseases.

An exercise test is used to monitor a person’s response to intense or moderate exercise. Blood samples are taken during exercise for testing.

Electromyography (EMG) uses small needle electrodes to measure the electrical currents in a muscle as it contracts. While an EMG can’t definitively diagnose metabolic disease, it can be used to rule out a number of other types of neuromuscular disease that cause similar patterns of weakness.

A muscle biopsy requires the removal of a small piece of muscle tissue for microscopic analysis. The procedure is done either surgically, with an incision to expose the target muscle, or with a needle. A skin biopsy is also sometimes performed.

Other tests that may be needed include an electrocardiogram to test heart function, and brain imaging studies such as CT or MRI scans.

Genetic tests, using a blood sample, can analyze the person’s genes for particular defects that cause metabolic disease, but these tests often aren’t necessary for diagnosis or for determining treatment.

What is the prognosis?

If the enzyme is completely lost there is rapid progression of the condition leading to death in infancy. If some enzyme activity remains, little or no progression with normal strength between episodes.